json = jsonWith (Right . fromList)jsonLast keeps the last occurrence of each key, using fromListWith (const id).
jsonLast = jsonWith (Right . fromListWith (const id))jsonAccum keeps wraps all values in arrays to keep duplicates, using fromListAccum.
jsonAccum = jsonWith (Right . fromListAccum)jsonNoDup fails if any object contains duplicate keys, using parseListNoDup.
jsonNoDup = jsonWith parseListNoDup